1. Field of the Invention
The present invention relates generally to a semiconductor integrated circuit (IC) test circuit and more specifically to a semiconductor IC supporting a co-debugging function and a semiconductor IC test system.
2. Description of the Related Art
Contemporary semiconductor devices implementing complicated protocols, such as Code Division Multiple Access (CDMA), Motion Picture Experts Group (MPEG), Voice Over Internet Protocol (VOIP), requiring real-time processing typically use system-on-a-chip (SOC) technology. This use of SOC technology is made possible in large part by dramatic improvements in sub-micron fabrication and design technologies.
SOC technology adopted in application areas using complicated protocols typically enables the computation of digital image and/or audio data. SOC technology as applied in such application areas typically includes the provision of a conventional signal processing unit. Moreover, SOC provides a real time operating system (RTOS) for managing system resources effectively. The RTOS provided by a SOC is typically executed by means of an application program running on the signal processing unit.
Where two or more processors, such as a Central Processing Unit (CPU) and a Digital Signal Processor (DSP), coexist in one SOC, a separate debugger is typically provided for each processor. Therefore, the two processors can not be co-debugged at the same time. The term “co-debugging” generally defines a process wherein a plurality of processors are debugged simultaneously using a single debugger.
Accordingly, in a conventional SOC implementation having two or more processors, each individual processor is connected to its own unique set of joint test action group (JTAG) pins. With this configuration, the processors are unable to transmit or receive signals, such as interrupts, to each other. This inability makes it impossible for co-debugging to occur. For example, if a SOC includes an ARM type CPU and a TEAK type DSP then an ARM debugger is typically used to debug the ARM CPU core and a TEAK debugger is used to debug the TEAK DSP core. As a result, the TEAK debugger cannot be stopped by setting a breakpoint to the TEAK debugger when the CPU core is being debugged.